Walhello is a spider based search engine developed in the Netherlands for the whole Internet. The Walhello spider is called "appie". This spider automatically downloads and indexes web pages and follows links found on the downloaded web pages. The Walhello search engine debuted in the summer of 2000 with a small index. Since then the index has grown to 2.3 billion indexed web pages. This is still significantly less than Google or Yahoo. Like most spider based search engines the ranking of search results is based on mathematical algorithms. Walhello is also doing research on the use of knowledge technology to improve the relevancy of search results. As an advanced search option proximity search functionality is provided, which allows users to define the proximity in which all search items must be found on a web site. A further functionality is the option to search for web pages written in a certain language.

The Walhello search engine is running on a cluster of Linux servers and is programmed in C.

The Walhello search engine provides an advertising solutions which is slightly different from the keyword based pay for positioning advertising used by many search engines. Walhello has created a small second index. This second index only contains paid listings, but is based on the same ranking technology used for the big index. Paid listings are shown if they match the search query.